I submitted a paper to a a good mathematics journal about 3 months ago, and have not heard anything yet (based on some of what I've heard this is fairly normal). During that time I made some significant edits to the introduction and some of the proofs (the original proofs were not incorrect but now they are easier to read/understand).
Should I send the updated version to the editor? If the paper is already being reviewed, then I wouldn't want to muddy the waters by submitting something new. That's my only concern at the moment. Thoughts?